Multichannel ablation with frequency differentiation

Abstract

Apparatus, including an energy generator, configured to supply first ablation power modulated at a first frequency and second ablation power modulated at a second frequency different from the first frequency. The apparatus also includes a probe, having at least one electrode coupled to receive the first and second ablation powers simultaneously and to dissipate the first and second ablation powers in body tissue in contact with the at least one electrode.

The invention claimed is: 
     
       1. Apparatus, comprising:
 a controller; 
 an energy generator operatively connected to the controller, the energy generator configured to supply first ablation power modulated at a first frequency and second ablation power modulated at a second frequency different from the first frequency, wherein the energy generator comprising a power source configured to supply the first and second ablation powers at a base radio frequency; first and second modulators, which are coupled to receive and to modulate the first and second ablation powers at the first and second frequencies, respectively; and a first power measuring unit having a first demodulator; and 
 a probe operatively connected to the energy generator, the probe comprising at least one electrode coupled to receive the first and second ablation powers simultaneously and to dissipate the first and second ablation powers in body tissue in contact with the at least one electrode, wherein the controller is configured to use an output from the first demodulator and the first and second modulated ablation powers to measure the power dissipated in the body tissue. 
 
     
     
       2. The apparatus according to  claim 1 , wherein the at least one electrode comprises a first electrode configured to receive the first ablation power, and a second electrode configured to receive the second ablation power, wherein, the first power measuring unit is coupled
 to the first electrode and configured to determine a first value of the first ablation power; and 
 a second power measuring unit is coupled to the second electrode and configured to determine a second value of the second ablation power. 
 
     
     
       3. The apparatus according to  claim 2 , wherein the first power measuring unit further comprises a second demodulator, the first and second demodulators being coupled to respectively receive signals at the base radio frequency and at the first frequency, and wherein the second power measuring unit comprises third and fourth demodulators coupled to respectively receive signals at the base radio frequency and at the second frequency. 
     
     
       4. The apparatus according to  claim 1 , wherein the modulation comprises phase modulation. 
     
     
       5. The apparatus according to  claim 1 , wherein the at least one electrode comprises a single electrode configured as a source electrode for the first ablation power and as a return electrode for the second ablation power. 
     
     
       6. The apparatus according to  claim 1 , wherein the at least one electrode comprises a first electrode configured as a source electrode for the first ablation power and a second electrode configured as a return electrode for the first ablation power. 
     
     
       7. The apparatus according to  claim 1 , wherein the at least one electrode comprises a first electrode configured as a source electrode for the first ablation power and a second electrode configured as a source electrode for the second ablation power. 
     
     
       8. The apparatus according to  claim 7 , and comprising a further electrode coupled to the body tissue and configured to act as a return electrode for the first and second ablation powers. 
     
     
       9. The apparatus according to  claim 1 , wherein the controller is configured to receive an indication of a value of at least one of the first and second ablation powers dissipated in the body tissue, and to determine an impedance of the body tissue in response to the value. 
     
     
       10. The apparatus according to  claim 9 , wherein the controller is configured to assess a degree of ablation of the body tissue in response to the impedance. 
     
     
       11. The apparatus according to  claim 9 , wherein the energy generator is configured to adjust a level of at least one of the first ablation power and the second ablation power in response to the impedance. 
     
     
       12. The apparatus according to  claim 1 , wherein at least one of the first ablation power and the second ablation power is supplied simultaneously in a unipolar mode and a bipolar mode. 
     
     
       13. A method, comprising:
 generating first ablation power modulated at a first frequency; 
 generating second ablation power modulated at a second frequency different from the first frequency; 
 supplying the first and second ablation powers at a base radio frequency; 
 receiving and modulating the first and second ablation powers at the first and second frequencies respectively; 
 coupling at least one electrode of a probe to receive the first and second ablation powers simultaneously and to dissipate the first and second ablation powers in body tissue in contact with the at least one electrode; and 
 measuring power dissipated into the body tissue using a first power measuring unit having a first demodulator using an output from the first demodulator and the first and second modulated ablation powers. 
 
     
     
       14. The method according to  claim 13 , wherein the at least one electrode comprises a first electrode configured to receive the first ablation power, and a second electrode configured to receive the second ablation power and comprising:
 coupling the first power measuring unit to the first electrode so as to determine a first value of the first ablation power; and 
 coupling a second power measuring unit to the second electrode so as to determine a second value of the second ablation power. 
 
     
     
       15. The method according to  claim 14 , wherein the first power measuring unit further comprises a second demodulator, the first second demodulators being coupled to respectively receive signals at the abase radio frequency and at the first frequency and wherein the second power measuring unit comprises third and fourth demodulators coupled to respectively receive signals at the base radio frequency and at the second frequency. 
     
     
       16. The method according to  claim 13 , wherein the modulating comprises phase modulating. 
     
     
       17. The method according to  claim 13 , wherein the at least one electrode comprises a single electrode configured as a source electrode for the first ablation power and as a return electrode for the second ablation power. 
     
     
       18. The method according to  claim 13 , wherein the at least one electrode comprises a first electrode configured as a source electrode for the first ablation power and a second electrode configured as a return electrode for the first ablation power. 
     
     
       19. The method according to  claim 13 , wherein the at least one electrode comprises a first electrode configured as a source electrode for the first ablation power and a second electrode configured as a source electrode for the second ablation power. 
     
     
       20. The method according to  claim 19 , and comprising coupling a further electrode to the body tissue to act as a return electrode for the first and second ablation powers. 
     
     
       21. The method according to  claim 13 , and comprising receiving an indication of a value of at least one of the first and second ablation powers dissipated in the body tissue, and determining an impedance of the body tissue in response to the value. 
     
     
       22. The method according to  claim 21 , and comprising assessing a degree of ablation of the body tissue in response to the impedance. 
     
     
       23. The method according to  claim 21 , and comprising adjusting a level of at least one of the first ablation power and the second ablation power in response to the impedance. 
     
     
       24. The method according to  claim 13 , and comprising supplying at least one of the first ablation power and the second ablation power simultaneously in a unipolar mode and a bipolar mode.